Lower-Hybrid-Wave Heating in the Alcator-ATokamak

Abstract
We report the results of injecting 90 kW of microwave power near the lower hybrid frequency into the Alcator-A tokamak through a two-waveguide array. The observed plasma heating is in disagreement with that expected from linear waveguide-plasma coupling theory. From these results and auxiliary rf probe measurements we infer the nonlinear formation of a high-k wave power spectrum at the plasma edge.